[Coin-ipopt] Ways to Trim Memory Usage?

Frank J. Iannarilli franki at aerodyne.com
Fri Jun 3 21:03:06 EDT 2005


I'm (successfully) running large application problems with IPOPT.  As I 
increase their sizing, I'm looking for ways to trim IPOPT's memory 

Some vital statistics for my present memory performance:

   Win32 (compiled with MinGW), MA19/MA27, and using the AMPL interface;
   Example problem -->> IPOPT itself eats 120MB memory:
        "Going to allocate
               double precision work space of size  3355970
               integer work space of size           4320981
         Number of variables           :    22869
            of which are fixed         :        0
         Number of constraints         :     9225
         Number of lower bounds        :    22869
         Number of upper bounds        :     4437
         Number of nonzeros in Jacobian:   248913
         Number of nonzeros in Hessian :   331776

Some ideas -- I'm looking for comments:

   - Tried limited-memory BFGS (IQUASI=-6/6)  --->> Saves about 20MB or 20%

   - Is the 120MB memory consumption commensurate with the problem sizing 
above?  Memory does not appear to be "leaking" over time.

   - Does the AMPL Subroutine Library (ASL) eat too much memory?  Would use 
of the F77 interface make for substantial savings?

   - Use a "better/different" linear solver (e.g, more recent Harwell 
routines, etc)?

   - Recompile to single-precision (is this even possible, not to mention 

   - ?????


Frank J. Iannarilli, franki at aerodyne.com
Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821 USA

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